An automobile steering wheel must satisfy certain requirements, such as minimizing or preventing vibration and providing for the safety of the driver in so far as possible. A wheel of low mass has a small amount of inertia which decreases the effect of road vibration and offers less resistance to turning. As to safety, desirably a steering wheel should deform, if necessary, upon driver impact during an accident absorbing the energy of the driver's body over a longer period of time, than would be the case if the wheel were rigid. Desirably, the wheel will tilt with the lower portion moving back and the upper portion relatively moving forward to offer a broader area for support of the driver's body if the protection afforded by the air bag is not sufficient, and also to tilt the section holding the air bag to deploy the air bag in a more desirable position. In extreme cases the wheel should break away.
Many designs and constructions for steering wheels have been proposed in the past. [See, for example, U.S. Pat. No. 4,920,821, shinto et al, and the numerous references cited therein.] However, there is still room for improvement, especially in making a lightweight wheel that is energy absorbing, but functionally strong enough to achieve its desired purpose.